1. Technical Field
Aspects of the present invention relate to a print data generating apparatus, a printing apparatus, a method to generate print data, and a computer usable medium therefor, and more specifically, to an apparatus, a method, and a computer usable medium to generate print data, by which a maximum density of colorant in a predetermined color to form a pixel can be adjusted, and a printing apparatus to print an image according to the print data.
2. Related Art
Conventionally, an inkjet printing apparatus, which ejects a plurality of colors of ink drops and white opaque ink drops onto a recording medium, has been known. In the inkjet printing apparatus, the inks are drawn from ink reservoirs to a plurality of ejecting channels provided in an inkjet head and ejected from nozzles at the end of the ejecting channels when actuators such as heater elements and piezoelectric elements are selectively activated. When an image is formed in colors, each of pixels composing the image is resolved, for example, into the three primary colors, which are cyan (C), magenta (M), and yellow (Y), thereafter, a colored pixel is formed as the inks adjusted in their densities are ejected onto the recording medium. In addition, a pixel in a black color can be reproduced in black (K) ink.
Further, in order to obtain images in higher quality, white (W) opaque ink can be used to reproduce white pixels and to form a base layer on a colored recording medium so that colored pixels can be reproduced clearly over the base layer regardless of the color of the recording medium. Such a printing apparatus is disclosed in, for example, Japanese Patent Provisional Publication No. 2005-153314. According to the printing apparatus in the publication, images in higher quality can be reproduced by adjusting amounts of the white ink and the colored inks to be ejected.
When images are formed on different types of recording sheets, color appearances of printed images may vary depending on colors of the recording sheets. Therefore, an inkjet printer capable of measuring whiteness of the recording to automatically determine amounts of inks to be ejected based on the whiteness is suggested so that color appearances of printed images can be substantially uniform regardless of the whiteness of the recording sheets. Such an inkjet printer is disclosed in, for example, Japanese Patent Provisional Publication No. H08-11310. According to the above publication, the inkjet printer receives light emitted from a light source and reflected on the recording sheet and detects whiteness of the recording sheet based on a difference of intensities between the emitted light and the reflected light. According to the detected whiteness and preliminarily obtained information concerning densities of the inks to be ejected, inkjet heads are driven to eject inks so that densities of the inks can be substantially uniformly adjusted regardless of whiteness of the recording sheets.